The environmental consequences of prolonged droughts are many and spread over a long period of time.Their increased frequency and intensity in the recent years, has posed a threat to mankind and economy. Especially so, in regions where droughts occur over prolonged periods. As the environmental consequences of prolonged droughts can be grave with domino effects too, the scientific community is studying the consequences and possible mitigation measures to lessen the incidence and impact of such droughts..
Droughts are extended periods of water shortage in a region. While even short periods of drought can cause irreversible damage to the economy, prolonged drought stretching over years, like those in Sahel and Horn of Africa regions, are capable of far-reaching environmental consequences. Recurring drought conditions can further bring about serious ecological catastrophes that cannot be ignored any more.
With persistent drought, the conditions worsen, with a far-reaching domino effect on the general economy of the nation. The consequences of prolonged drought are many, namely environmental, agricultural, health, economic, social and socio-political, all of which depend upon the type of drought conditions prevailing. However, herein we shall examine only the environmental consequences of prolonged drought.
These typify prolonged periods of drought with precipitation lesser than the climatological mean of that area.
A significant depletion in surface water causing low stream flow and drying up of aquifers, lakes, rivers and other water reserves. This may also happen as a fallout of excessive water usage, without adequate replenishment.
Prolonged conditions of soil erosion and loss of soil moisture, as well as external factors like reduced precipitation and poorly planned agricultural practices, can cause such conditions of agricultural droughts.
Dust Bowls are quite typical of prolonged agricultural droughts, where severe drought coupled with lack of adequate farming techniques have failed to control soil erosion.
Dust Storms are a meteorological phenomenon where the loose soil and dust are transported over distances to be deposited elsewhere. This obviously has an impact on the regional weather conditions as well as the global climate. Thus there occurs an increase in cloud formation that raises the heat blanket effect.
Changes in the geophysics of the region occur, as in soil erosion, causing further change to the immediate environment.
The air quality is also affected with increase in dust and pollutants.
Habitat damage in the biome is usually caused by hydrological droughts or sometimes meteorological droughts, affecting both the terrestrial and aquatic biome.The micro environment of the region often undergoes a permanent change as well, with the insect kingdom being the most affected. There is an overall loss of biodiversity.
Shortages of Water
This is typical of hydrological and meteorological droughts, cause dried up water aquifers and changes in the hydrology, with reduced stream flows. Increased groundwater depletion also causes reduced recharge and land subsidence.
Changes in Water Chemistry
These may occur with change in salinity levels, increase in water temperature, pH, turbidity or dissolved oxygen.
Wildfires and Bushfires
Such fires are common in regions of prolonged droughts, where lack of precipitation, loss of top soil and arid conditions induce such wildfire hazards.
This is an increasingly alarming prospect of prolonged droughts, as has been seen in the Horn of Africa.